1. Field of the Invention
The present invention relates to aircraft steering systems and more particularly to a method and system for steering large aircraft.
2. Description of the Prior Art
In the patent literature, U.S. Pat. No. 3,488,020 to Scherer assigned to The Boeing Company is illustrative of an aircraft steering system comprising a steerable nose gear and having at least one main wheel truck which rotates opposite the nose gear when the aircraft is negotiating a tight turn radius. In contrast the present invention utilizes steerable nose and main gear in which each is utilized separately to control the aircraft, the nose gear for high speed taxing and main gear for low speed taxing.
U.S. Pat. No. 2,254,935 relates to rack and pinion steering.
U.S. Pat. No. 3,007,655 shows electrical actuation steering.
U.S. Pat. No. 2,621,002 shows main post steering of a gear.
U.S. Pat. No. 2,734,589 shows speed response control.
U.S. Pat. No. 2,756,949 is illustrative a swiveling gear.
U.S. Pat. No. 2,906,474 is illustrative of speed responsive control; and
U.S. Pat. No. 3,067,832 relates to velocity modulation.
What will become understood and appreciated hereinafter is that the more efficient the "steering device" is, the more control the main gears have over the more gear in the turning of the aircraft. In fact the ultimate solution would be realized if the "steering device" efficiency were 100%, then the nose gear steering torque requirements would be zero. The nose gear would need to be "fully castoring" as all the steering torque would be generated by the main gears. However, due to the power the main gears would have over the nose in turning the aircraft, the sensitivity of the overall steering of the aircraft may be a problem. As a consequence it is advisable to retain the nose gear steering as a controller (with the main gears following as in Boeing type 747 aircraft) up to the maximum required nose steering angle.